1. Field of the Invention
The present invention relates to an optical sight, more particularly to an optical sight having a glow-in-the-dark aim indicator.
2. Description of the Related Art
FIGS. 1 and 2 show a conventional optical sight for use with a firearm. The optical sight includes an outer barrel 1 having first and second ends, an objective lens unit 2 mounted to the first end of the outer barrel 1, an ocular lens unit 3 mounted to the second end of the outer barrel 1, a magnification unit 4 used for magnification adjustment, a pair of adjustment units 5 used for elevation and windage adjustment, and an aiming unit 6.
The aiming unit 6 includes a plate member 61 mounted to a rear end of an inner barrel 401 of the magnification unit 4, and a lighting unit 62. The plate member 61 includes a reticle 611 used during aiming. The lighting unit 62 includes a securing seat 621 mounted to a rear end portion of the outer barrel 1, a potentiometer 622 disposed in the securing seat 621, a circuit board 623 also disposed in the securing seat 621, a battery holder 624 mounted to the securing seat 621, a battery 625 disposed in the battery holder 624, an adjusting ring 626 sleeved on the battery holder 624, a seal cover 627 sealingly mounted to the battery holder 624, are fraction ring 628 mounted in the outer barrel 1 and disposed to the rear of the plate member 61, and a light emitting diode (LED) 629 mounted on the refraction ring 628.
When using the optical sight in a low-light environment (e.g., at night), the LED 629 may be activated by rotating the adjusting ring 626. Therefore, the light of the LED 629 is directed onto the reticle 611 of the plate member 61, at least partly through refraction by the refraction ring 628. Hence, the user is able to make use of the optical sight even in a dark environment.
However, the presence of the lighting unit 62, which is complicated in structure, increases the overall costs and assembly time of the optical sight. Furthermore, the watertight and airtight capabilities of the outer barrel 1 may be compromised if the lighting unit 62 is not precisely manufactured.